WO2012039233A1 - Lithographic printing plate original - Google Patents

Abstract

The purpose of the present invention is to provide a lithographic printing plate original with which it is possible to prevent blooming without using a specific polymerization initiator, infrared absorber, and the like. The lithographic printing plate original comprises a support and an image-forming layer containing a radiation-photosensitive composition including a radical-polymerizable component, an infrared absorber, and a radical polymerization initiator, wherein the radiation-photosensitive composition includes a fluorinated copolymer that has essentially no hydrophilic segment.

Description

Planographic printing plate precursor

The present invention relates to a lithographic printing plate precursor having a negative radiation-sensitive composition, and particularly to a negative lithographic printing plate precursor having a good shelf life.

Negative-type radiation-sensitive compositions are used in particular for lithographic printing plate precursors, but such compositions generally comprise a radiation-sensitive component, a radically polymerizable component, and an initiator system. Recent developments in the field of lithographic printing plate precursors have resulted in radiation-sensitive compositions that can be imaged by lasers or laser diodes, and more specifically on-machine imaged and / or developed. Is directed. Laser exposure does not require a silver halide film like an imaged “mask” because the laser can be controlled directly by a computer. High performance lasers or laser diodes used in commercially available imagesetters generally emit radiation having a wavelength of at least 700 nm, and thus the radiation sensitive composition is in the near infrared region of the electromagnetic spectrum. Alternatively, it is necessary to sensitize in the infrared region. However, other useful radiation-sensitive compositions are configured to image with ultraviolet or visible radiation.

There are two types of lithographic printing plate precursors: negative and positive. In the case of a negative printing plate precursor, the exposed areas in the radiation-sensitive composition are cured, and the unexposed areas are dissolved in the developer and removed. On the other hand, in the positive type printing plate precursor, the exposed area becomes soluble in the developer, dissolved and removed, and the unexposed area remains on the support.

Various negative-type radiation-sensitive compositions and lithographic printing plate precursors containing a reactive polymer binder are known to those skilled in the art. These radiation-sensitive compositions generally include a radiation-sensitive component, a radically polymerizable component, an initiator system, and various additional components to improve developability, photosensitivity, and the like.

The various radiation-sensitive compositions in this technical field contain many salts as components. For example, IR dyes for infrared absorbers use a wide variety of ionic compounds, and polymerization initiators also use a wide variety of ionic compounds. Such ionic compounds tend to move, gather, localize, and further crystallize (this state is called “blooming”) in the radiation-sensitive composition during storage. Have. When a planographic printing plate precursor that has undergone blooming is exposed to form an image, curing of the blooming portion becomes insufficient, resulting in uneven curing, and in some cases it may not be cured, which has been a problem in the past. .

JP 2009-538446 A

As one method for preventing blooming of a lithographic printing plate precursor, JP-A-2009-538446 discloses an iodonium borate initiator having a specific structure that does not cause blooming in a coating film of a radiation-sensitive composition. It has been proposed to use a composition. However, it is preferable that blooming can be prevented without using a specific polymerization initiator, infrared absorber or the like.

Blooming shortens the shelf life of lithographic printing plate precursors and makes image formation unstable. Accordingly, there is a need for a lithographic printing plate precursor that does not cause blooming and has an improved shelf life.

The inventors of the present application have found that blooming is accelerated by moisture in the coating film of the radiation-sensitive composition. The lithographic printing plate precursor is dried and packed after preparation. When the planographic printing plate precursor is stored for a long period of time, moisture in the package penetrates from the surface of the coating film. Also, if left unpacked after being unpacked, moisture contained in the ambient air penetrates from the surface of the coating film. Water molecules have polarity, and this polarity is thought to promote localization of ionic compounds.

The inventor of the present application has found that when a fluorinated polymer having no hydrophilic portion is added to the radiation-sensitive composition, migration and localization of the ionic compound are suppressed, and the present invention has been completed. The present invention is a lithographic printing plate precursor comprising a support, and an image forming layer containing a radiation-sensitive composition containing a radical polymerizable component, an infrared absorber and a radical polymerization initiator, the radiation plate Provided is a lithographic printing plate precursor in which the photosensitive composition comprises a fluorinated polymer having no hydrophilic portion.

The lithographic printing plate precursor according to the present invention uses a fluorinated polymer having substantially no hydrophilic portion as an additive for the radiation-sensitive composition. Here, “substantially does not have a hydrophilic portion” means that the function as a surfactant is not expressed because the fluorinated polymer has substantially no hydrophilicity. The surfactant has a hydrophilic group and a hydrophobic group in its structure, and the hydrophilic group easily binds to a water molecule. If a hydrophilic group is present, the water molecule is taken into the coating film. It will be easier and will help in the direction of blooming.

As used herein, “hydrophilic moiety” refers to a moiety that interacts strongly with water in the structure of a compound, and typically includes a cationic group, an anionic group, an acidic group, a polyoxyethylene group, and the like. Say. _{Specifically, -COOH, -OH, -NH 2,} -NHCONH 2, - (OCH 2 CH 2) -, - SO 3 H, -SO 3 M, -OSO 3 H, -OSO 3 M, -COOM , NR ₃ X (wherein M is an alkali metal or —NH ₄ , R is an alkyl group, and X is a halogen). The fluorinated polymer that can be used in the lithographic printing plate precursor according to the invention does not substantially contain such a hydrophilic portion.

One example of the fluorinated polymer that can be used in the lithographic printing plate precursor according to the present invention is a fluorinated copolymer represented by the following formula (A).

Formula (A):

(In the above formula,
R ₁ and R ₂ are hydrogen or a methyl group,
Rf represents an aliphatic group substituted with a fluorine atom;
Z represents a divalent organic group, and X represents any organic group substantially free of a cationic group, an anionic group, an acidic group or a polyoxyethylene group.

The fluorinated copolymer of the formula (A) preferably contains 10 to 97 mol% of the monomer unit of the formula (I) and 3 to 90 mol% of the monomer unit of the formula (II).

The Rf group of the formula (A) is preferably a fluoroaliphatic group having 1 to 20 carbon atoms and having at least two of the terminal three hydrogen atoms substituted with fluorine atoms.

The Rf group is usually saturated and is generally a monovalent or divalent aliphatic group. The aliphatic group has a linear, branched, cyclic, or combination thereof (for example, an alkylcycloaliphatic group). The fluoroaliphatic backbone can include a chain of oxygen and / or trivalent nitrogen heteroatoms bonded only to carbon atoms. This heteroatom provides a stable bond between the fluorocarbon groups and does not interfere with the inert properties of the Rf group.

The Rf group has 1 to 20, preferably 4 to 10, carbon atoms, and at least two of the three hydrogen atoms at the end thereof are substituted with fluorine atoms. Examples of the terminal of such an Rf group include CF ₃ CF ₂ CF ₂ —. In particular, the Rf group is preferably a perfluoroalkyl group. A perfluoroalkyl group is a substantially completely or fully fluorinated alkyl group such as C _n F _{2n + 1} (n is an integer of 3 or more).

When the Rf group has 1 to 20 carbon atoms, the effect of preventing the localization of the ionic compound is large. Particularly, when the Rf group has 4 to 10 carbon atoms, the effect of preventing the localization of the ionic compound. Is even bigger. On the other hand, when the number of carbon atoms of the Rf group is 21 or more, the solubility of the obtained copolymer in the solvent is lowered, and a restriction is imposed on the solvent when used for the lithographic printing plate precursor.

Z in the formula (A) represents a divalent organic group, such as a —CO—O— group, a —CO—NH— group, a CO—O—Q— group, a —CO—NH—Q group, and the like. Here, the Q group refers to a methylene group, an ethylene group, a —CH ₂ —CH ₂ —CO—O— group, or a —CH ₂ —CH ₂ —O—CO— group.

X in the formula (A) is an arbitrary organic group that does not contain a cationic group, an anionic group, an acidic group, or a polyoxyethylene group. Examples of cationic groups, anionic groups, acidic groups, and polyoxyethylene groups not included in X include, for example, trialkylammonium groups as cationic groups, ammonium groups, carboxylate groups as anionic groups, Sulfonate groups, phosphonate groups, etc., such as carboxyl groups, sulfonic acid groups, phosphonic acid groups, sulfate ester groups, phosphate ester groups, etc., these groups are all groups imparting hydrophilicity, such as The fluorinated polymer having a group is substantially not used in the present invention.

Preferably X is a —CO—A—Y group. A represents an oxygen atom or NR ⁴ —, wherein R ⁴ represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. Y is selected from the group consisting of an alkyl group which may have a substituent, an aryl group which may have a substituent, and a monovalent organic group having an unsaturated group.

Examples of the monomer containing X of the fluorinated polymer of the present invention include acrylic esters such as alkyl acrylate (the alkyl group preferably has 1 to 20 carbon atoms), (specifically, for example, Methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, ethyl hexyl acrylate, octyl acrylate, tert-octyl acrylate, chloroethyl acrylate, 2,2-dimethylhydroxypropyl acrylate, 5- Hydroxypentyl acrylate, trimethylolpropane monoacrylate, pentaerythritol monoacrylate, glycidyl acrylate, benzyl acrylate, methoxybenzyl acrylate, furfuryl acrylate, tetrahydrofurfuryl acrylate ), Aryl acrylates (for example, phenyl acrylate, etc.), methacrylic acid esters (for example, those having 1 to 20 carbon atoms in the alkyl group) (for example, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl) Methacrylate, amyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, chlorobenzyl methacrylate, octyl methacrylate, 4-hydroxybutyl methacrylate, 5-hydroxypentyl methacrylate, 2,2-dimethyl-3-hydroxypropyl methacrylate, trimethylol Propane monomethacrylate, pentaerythritol monomethacrylate, glycidyl methacrylate, furf Yl methacrylate, tetrahydrofurfuryl methacrylate, etc.), aryl methacrylate (eg, phenyl methacrylate, cresyl methacrylate, naphthyl methacrylate, etc.), styrene such as styrene, alkyl styrene (eg, methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, diethyl) Styrene, isopropyl styrene, butyl styrene, hexyl styrene, cyclohexyl styrene, decyl styrene, benzyl styrene, chloromethyl styrene, trifluoromethyl styrene, ethoxymethyl styrene, acetoxymethyl styrene, etc.), alkoxy styrene (eg methoxy styrene, 4-methoxy- 3-methylstyrene, dimethoxystyrene, etc.), halogen styrene (for example, chlors) Len, dichlorostyrene, trichlorostyrene, tetrachlorostyrene, pentachlorostyrene, prom styrene, dibromostyrene, iodostyrene, fluorostyrene, trifluorostyrene, 2-bromo-4-trifluoromethylstyrene, 4-fluoro- 3-trifluoromethylstyrene etc.), acrylonitrile, methacrylonitrile and the like.

Also included are monomers having the following structure.

(In the formula, X and Y each independently represent an oxygen atom, a sulfur atom or —N (R ¹² ) —. Z represents an oxygen atom, a sulfur atom, —N (R ¹² ) — or a phenylene group. ¹ to R ¹² each independently represents a monovalent substituent.)

In the general formula (1), R ¹ to R ³ each independently represents a monovalent substituent. For example, R ¹ may have a hydrogen atom or a monovalent organic group, for example, a substituent. An alkyl group etc. are mentioned, Especially, a hydrogen atom, a methyl group, a methyl alkoxy group, and a methyl ester group are preferable. R ² and R ³ may each independently have a hydrogen atom, a halogen atom, an amino group, a dialkylamino group, a carboxyl group, an alkoxycarbonyl group, a sulfo group, a nitro group, a cyano group, or a substituent. Alkyl group, aryl group which may have a substituent, alkoxy group which may have a substituent, aryloxy group which may have a substituent, alkylamino group which may have a substituent, substituted An arylamino group that may have a group, an alkylsulfonyl group that may have a substituent, an arylsulfonyl group that may have a substituent, and the like. Among them, a hydrogen atom, a carboxyl group, an alkoxycarbonyl group An alkyl group which may have a substituent and an aryl group which may have a substituent are preferable. Here, examples of the substituent that can be introduced include a methoxycarbonyl group, an ethoxycarbonyl group, an isopropyloxycarbonyl group, a methyl group, an ethyl group, and a phenyl group. X represents an oxygen atom, a sulfur atom, or —N (R ¹² ) —, and examples of R ¹² include an alkyl group which may have a substituent.

In the general formula (2), R ⁴ to R ⁸ each independently represents a monovalent substituent, such as a hydrogen atom, a halogen atom, an amino group, a dialkylamino group, a carboxyl group, an alkoxycarbonyl group, a sulfo group. Group, nitro group, cyano group, alkyl group which may have a substituent, aryl group which may have a substituent, alkoxy group which may have a substituent, aryl which may have a substituent An oxy group, an alkylamino group which may have a substituent, an arylamino group which may have a substituent, an alkylsulfonyl group which may have a substituent, an arylsulfonyl group which may have a substituent Among them, a hydrogen atom, a carboxyl group, an alkoxycarbonyl group, an alkyl group which may have a substituent, and an aryl group which may have a substituent are preferable. Examples of the substituent that can be introduced include those listed in the general formula (1). Y represents an oxygen atom, a sulfur atom, or —N (R ¹² ) —. Examples of R ¹² include those listed in general formula (1).

In the general formula (3), R ⁹ to R ¹¹ each independently represents a monovalent substituent, such as a hydrogen atom, a halogen atom, an amino group, a dialkylamino group, a carboxyl group, an alkoxycarbonyl group, a sulfo group. Group, nitro group, cyano group, alkyl group which may have a substituent, aryl group which may have a substituent, alkoxy group which may have a substituent, aryl which may have a substituent An oxy group, an alkylamino group which may have a substituent, an arylamino group which may have a substituent, an alkylsulfonyl group which may have a substituent, an arylsulfonyl group which may have a substituent Among them, a hydrogen atom, a carboxyl group, an alkoxycarbonyl group, an alkyl group which may have a substituent, and an aryl group which may have a substituent are preferable. Here, as a substituent, what was mentioned in General formula (1) is illustrated similarly. Z represents an oxygen atom, a sulfur atom, —N (R ¹² ) — or a phenylene group. Examples of R ¹² include those listed in general formula (1).
Among these, a methacryloyloxy group represented by the general formula (1) is preferable.

The monomer unit of the formula (I) is preferably present in the fluorinated polymer in an amount of 10 to 97 mol%. If it is less than 10 mol%, the solubility in a coating solvent is lowered, which is not preferable. On the other hand, if it exceeds 97 mol%, the hydrophobicity of the fluorinated polymer is weakened, and as a result the effect of the present case is weakened. More preferably, the amount of monomer units of formula (I) is from 50% to 97%.

The monomer unit of the formula (II) is preferably present in the fluorinated polymer in an amount of 3 to 90 mol%. If it is less than 3 mol%, the hydrophobicity of the fluorinated polymer is weakened, and as a result the effect of the present case is weakened. Moreover, when it exceeds 90 mol%, the solubility with respect to a coating solvent falls and it is not preferable. More preferably, the amount of monomer units of formula (II) is from 3% to 50%.

The fluorinated copolymer of the present invention can be a block copolymer or a random copolymer.

The fluorinated copolymer of the present invention preferably has a monomer unit having a maleimide skeleton represented by the following formula (1) as necessary.

(In the formula, R represents a hydrogen atom or a hydrocarbon group selected from the group consisting of an optionally substituted alkyl group, alkenyl group, and aryl group.)

Such a fluorine-containing resin having a maleimide skeleton increases the hydrophobicity of the fluorinated polymer, and is further excellent in the improvement effect of this case. The maleimide skeleton is more preferably an N-substituted maleimide skeleton, and even more preferably an N-cyclic hydrocarbon substituted maleimide skeleton.

Examples of a method for incorporating the maleimide skeleton into the structure of the fluororesin include, for example, a method of adding an amine compound to a maleic anhydride-containing polymer (imidization), a (meth) acrylate having an Rf group, and a hydroxyl group (meta ) Acrylate, (meth) acrylic acid, (meth) acrylate having a glycidyl group, and a method of polymerizing a compound having a maleimide skeleton. Such methods include, for example, JP 59-24844, JP 61-34046, JP 61-128243, JP 61-162039, JP 61-250048, JP Nos. 62-94840, 62-153305, 62-283108, and the like. A typical example of the maleic anhydride-containing polymer is a styrene-maleic anhydride copolymer.

Examples of the compound having a maleimide skeleton include N-phenylmaleimide, N-phenylmethylmaleimide, N-chlorophenylmaleimide, N-methoxyphenylmaleimide, N-methylphenylmaleimide, N-dimethylphenylmaleimide, N-ethylphenylmaleimide, N-diethylphenylmaleimide, N-nitrophenylmaleimide, N-phenoxyphenylmaleimide, N-hydroxyphenylmaleimide, N-carboxyphenylmaleimide, N-phenylcarbonylphenylmaleimide, N-methylmaleimide, N-ethylmaleimide, N-vinyl N-substituted maleimides such as maleimide, N-allylmaleimide, N-cyclohexylmaleimide and N-laurylmaleimide; non-N-substituted maleimi such as maleimide Kind, and the like. In the substituted phenyl group bonded to the maleimides, the substituent may be bonded to any other carbon atom not bonded to the N atom in the phenyl group.

Specific examples of the fluorinated polymer having no hydrophilic portion that can be used in the lithographic printing plate precursor according to the invention include the following fluorinated polymers. The ratio in a formula represents mol%.

These compounds have no surface active action. These fluorinated polymers may be used alone or as a mixture of plural kinds.

The total amount of the fluorinated polymer having no hydrophilic portion is at least 0.01% by mass based on the dry weight of the image forming layer, and is present in the image forming layer in a maximum amount of 10% by mass. Preferably, it is present in an amount of 0.1 to 1% by weight, based on the dry weight of the image forming layer. When the amount of the fluorinated polymer is less than 0.01% by mass, the effect of the present case is weakened, which is not preferable. Moreover, when it exceeds 10 mass%, the image line intensity | strength at the time of exposure will become weak, and is not preferable.

<Radically polymerizable component>
The radiation-sensitive composition of the present invention contains a neutralized phosphate ester compound having a (meth) acryloyl group as a polymerizable compound. The image forming layer containing a neutralized phosphate ester compound having a (meth) acryloyl group used in the present invention undergoes addition polymerization and cures by the action of a photopolymerization initiator when irradiated with an activating light beam. The exposed lithographic printing plate precursor is treated with a suitable developer or the like to remove unexposed portions and form a negative image.

The phosphoric acid ester compound having a (meth) acryloyl group that can be used in the present invention is a phosphoric acid ester having at least one (meth) acryloyl group in the structural formula. It is a phosphoric acid (meth) acrylate monomer.

(Wherein R ₁ is a hydrogen atom or a methyl group, R ₂ is a hydrogen atom or a methyl group, and n is an integer of 1 to 6)

In the case of taking a phosphate methacrylate structure, the presence of polyalkylene glycol chains such as PEG (polyethylene glycol) chains and PPG (polypropylene glycol) chains in the molecular structure also helps improve the good developability on the printing press. Is preferable. Examples of the compound included in the above structural formula include the following. All of these are sold by Unichemical Corporation.

In the present invention, these phosphoric acid (meth) acrylate monomers are neutralized with a base. As a neutralization method, 1 to 2 equivalents of a base in terms of mole is added to the phosphoric acid (meth) acrylate monomer. Examples of the base that can be used for neutralization include alkali metal hydroxides, alkaline earth metal hydroxides, and organic amines. Among them, alkali metal hydroxides and hydroxylalkylamines are particularly preferable. Examples of the alkali metal hydroxide include lithium hydroxide, sodium hydroxide, and potassium hydroxide. Examples of the hydroxylalkylamine include methylhydroxylamine, ethylhydroxylamine, triethanolamine and the like.

The ratio of the neutralized phosphoric acid (meth) acrylate monomer is 5 to 20% by mass with respect to the total solid content constituting the layer composed of the photosensitive composition. If it is less than 5% by mass, the adhesion to the support is inferior, and ink stains occur in the non-image area due to changes over time. If the ratio of neutralization exceeds 20% by mass, the mechanical strength of the image forming area becomes weak.

In the photosensitive composition of the present invention, it is desirable to include a polymerizable compound other than the phosphoric acid (meth) acrylate monomer as the polymerizable compound. For example, it can be used in the form of a monomer, oligomer, polymer, or a mixture thereof.

Examples of monomers or oligomers include unsaturated carboxylic acids (eg, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid) and esters and amides thereof, preferably unsaturated carboxylic acids. An ester of an acid and an aliphatic polyhydric alcohol compound and an amide of an unsaturated carboxylic acid and an aliphatic polyamine compound are used.

In addition, unsaturated carboxylic acid ester having a nucleophilic substituent such as hydroxyl group, amino group, mercapto group, amide and monofunctional or polyfunctional isocyanate, addition reaction product of epoxy, monofunctional or polyfunctional A dehydration condensation reaction product with a functional carboxylic acid is also preferably used.

In addition, an addition reaction product of an unsaturated carboxylic acid ester or amide having an electrophilic substituent such as an isocyanate group or an epoxy group with a monofunctional or polyfunctional alcohol, amine or thiol, halogen A substitution reaction product of an unsaturated carboxylic acid ester or amide having a leaving substituent such as a group or a tosyloxy group with a monofunctional or polyfunctional alcohol, amine or thiol is also suitable. Moreover, the compound group replaced by unsaturated phosphonic acid, styrene, etc. can also be used instead of said unsaturated carboxylic acid.

Specific examples of the radical polymerizable compound that is an ester of an aliphatic polyhydric alcohol compound and an unsaturated carboxylic acid include acrylic acid esters such as ethylene glycol diacrylate, triethylene glycol diacrylate, polyethylene glycol methyl ether acrylate, 1, 3-butanediol diacrylate, tetramethylene glycol diacrylate, propylene glycol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylolpropane tri (acryloyloxypropyl) ether, trimethylolethane triacrylate, hexanediol diacrylate Acrylate, 1,4-cyclohexanediol diacrylate, tetraethylene glycol diacrylate, Taerythritol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol diacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, sorbitol triacrylate, sorbitol tetraacrylate, sorbitol pentaacrylate, sorbitol hexaacrylate, tri (Acryloyloxyethyl) isocyanurate, polyester acrylate oligomer, and the like.

Methacrylic acid esters include tetramethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol methyl ether methacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, ethylene glycol dimethacrylate, 1,3 -Butanediol dimethacrylate, hexanediol dimethacrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, dipentaerythritol dimethacrylate, dipentaerythritol pentamethacrylate, dipentaerythritol hexamethacrylate, sorbitol trimethacrylate Relate, sorbitol tetramethacrylate, bis [p- (3--methacryloxy-2-hydroxypropoxy) phenyl] dimethyl methane, bis - [p- (methacryloxyethoxy) phenyl] dimethyl methane.

Itaconic acid esters include ethylene glycol diitaconate, propylene glycol diitaconate, 1,3-butanediol diitaconate, 1,4-butanediol diitaconate, tetramethylene glycol diitaconate, pentaerythritol diitaconate And sorbitol tetritaconate.

Examples of crotonic acid esters include ethylene glycol dicrotonate, tetramethylene glycol dicrotonate, pentaerythritol dicrotonate, and sorbitol tetradicrotonate.

Examples of isocrotonic acid esters include ethylene glycol diisocrotonate, pentaerythritol diisocrotonate, and sorbitol tetraisocrotonate.

Examples of maleic acid esters include ethylene glycol dimaleate, triethylene glycol dimaleate, pentaerythritol dimaleate, and sorbitol tetramaleate.

Examples of other esters include aliphatic alcohol esters described in JP-B-46-27926, JP-B-51-47334, JP-A-57-196231, JP-A-59-5240, JP-A-59-5241. Those having an aromatic skeleton described in JP-A-2-226149 and those containing an amino group described in JP-A-1-165613 are also preferably used.

Specific examples of the radical polymerizable compound that is an amide of an aliphatic polyvalent amine compound and an unsaturated carboxylic acid include methylene bis-acrylamide, methylene bis-methacrylamide, 1,6-hexamethylene bis-acrylamide, 1,6 -Hexamethylene bis-methacrylamide, diethylenetriamine trisacrylamide, xylylene bisacrylamide, xylylene bismethacrylamide and the like. Examples of other preferable amide-based monomers include those having a cyclohexylene structure described in JP-B-54-21726.

In addition, urethane-based addition polymerizable compounds produced by using an addition reaction of isocyanate and hydroxyl group are also suitable, and specific examples thereof include, for example, one molecule described in JP-B-48-41708. In the polyisocyanate compound having two or more isocyanate groups, CH ₂ ═C (R ¹ ) COOCH ₂ CH (R ² ) OH (where R ¹ and R ² are each independently H or CH ₃ . And a vinylurethane compound containing two or more polymerizable vinyl groups in one molecule to which a vinyl monomer containing a hydroxyl group represented by (1) is added.

Also, urethane acrylates such as those described in JP-A-51-37193, JP-B-2-32293, and JP-B-2-16765, JP-B-58-49860, JP-B-56-17654, Urethane compounds having an ethylene oxide skeleton described in JP-B-62-39417 and JP-B-62-39418 are also suitable.

Furthermore, radical polymerizable compounds having an amino structure or a sulfide structure in the molecule described in JP-A-63-277653, JP-A-63-260909, and JP-A-1-105238 may be used. In addition, specific unsaturated compounds described in JP-B-46-43946, JP-B-1-40337, and JP-B-1-40336, and vinylphosphonic acid compounds described in JP-A-2-25493 can also be exemplified. . In some cases, a structure containing a perfluoroalkyl group described in JP-A-61-22048 is preferably used. Furthermore, Journal of Japan Adhesion Association vol. 20, no. 7, pages 300 to 308 (1984) as photocurable monomers and oligomers can also be used.

Examples of the radical polymerizable compound having at least one ethylenically unsaturated double bond of the polymer type include, for example, JP-A-48-64183 and JP-B-49-43191 in addition to the above-mentioned monomer or oligomer polymer. Polyfunctional acrylates and methacrylates such as polyester acrylates and epoxy acrylates obtained by reacting an epoxy resin with (meth) acrylic acid, as described in JP-B-52-30490, each publication.

The polymerizable compound of the present invention is insoluble in a wet developer or dampening water / printing ink after exposure to radiation such as ultraviolet (UV), visible light, and infrared (IR). As such, it is present in a sufficient amount in the photosensitive composition. Specifically, the content is preferably 5 to 80% by mass, more preferably 10 to 70% by mass, based on all components of the photosensitive composition.

<Infrared absorber>

Preferred infrared absorbers that can be used in the lithographic printing plate precursor of the present invention are squarylium dyes, croconate dyes, triarylamine dyes, thiazolium dyes, indolium dyes, oxazolium dyes, cyanine and merocyanine dyes, polyaniline dyes, polypyrrole dyes, Polythiophene dyes, chalcogenopyryl arylidene and bis (chalcogenopyrrillo) polymethine dyes, oxyindolizine dyes, pyrylium dyes, and phthalocyanine pigments. Other useful classes include azulenium and xanthene dyes, as well as carbon black, metal carbides, borides, nitrides, carbonitrides, and bronze structured oxides.

Among these, as the infrared absorber, a near-infrared absorbing cation dye represented by the following formula is preferable because the photopolymerization initiator efficiently exhibits a polymerization function.
D ⁺ A ⁻

(In the formula, D ⁺ represents a cationic dye having absorption in the near-infrared region, and A ⁻ represents an anion. A ⁻ may be in the dye molecule and may take the structure of an inner salt.)

Examples of cationic dyes having absorption in the near infrared region include cyanine dyes, triarylmethane dyes, aminium dyes, diimmonium dyes, and dyes having absorption in the near infrared region. As specific examples of the cationic dye having absorption in the near infrared region, the following can be used.

Examples of anions include halogen anions, ClO ₄ ⁻ , PF ₆ ⁻ , BF ₄ ⁻ , SbF ₆ ⁻ , CH ₃ SO ₃ ⁻ , CF ₃ SO ₃ ⁻ , C ₆ H ₅ SO ₃ ⁻ , and CH ₃ C ₆ H _4. SO ₃ ⁻ , HOC ₆ H ₄ SO ₃ ⁻ , ClC ₆ H ₄ SO ₃ ⁻ , and the quaternary boron anion include a boron anion represented by the above formula (1). As the boron anion, triphenyl n-butylboron anion and trinaphthyl n-butylboron anion are preferable.

When a dye is used as the infrared absorber, the content of the dye is preferably in the range of 0.5 to 15% by mass, particularly preferably in the range of 1 to 10% by mass, based on the total solid content of the photosensitive composition. . When the pigment content is less than 0.5% by mass, the infrared absorption is insufficient. When the pigment content exceeds 15% by mass, the infrared absorption substantially reaches saturation, and the effect of addition is improved. It is not preferable because it tends to be absent.

<Radical polymerization initiator>
The photosensitive composition of the present invention preferably contains the polymerizable compound described above and a photopolymerization initiator for generating initiating free radicals. Any photopolymerization initiator can be used as long as it can initiate polymerization of the above-described polymerizable compound. Photoinitiators that are active against electromagnetic radiation in the ultraviolet, visible, and / or infrared spectral ranges corresponding to a spectral range of about 300-1400 nm can be used. Such photoinitiator systems include, for example, trichloromethyltriazine present alone or with a photosensitizer, as described in US Pat. No. 4,997,745; Diaryl iodonium salts and photosensitizers as described in US Pat. No. 5,546,258; for example with trichloromethyltriazine as described in US Pat. No. 5,599,650 Spectral sensitizers for visible light activation; polycarboxylic acid coinitiators such as anilino-N, N-2 acetic acid, as described in US Pat. No. 5,942,372, and diaryls Iodonium salts, titanocenes, haloalkyltriazines, hexaarylbisimidizoles, borates, and compounds substituted by alkoxy or acyloxy groups 3-ketocoumarin for UV and visible light activation, with secondary co-initiators such as photo-oxidants containing cyclic nitrogen atoms; described in US Pat. No. 5,368,990 Such as cyanine dyes, diaryliodonium salts, and co-initiators having a carboxylic acid group attached to the N, O, or S group directly attached to the aromatic ring via a methylene group; US Pat. No. 5,496 , 903, cyanine dyes for infrared activity together with trichloromethyltriazine and organoboron salts; as described in US Pat. No. 6,309,792 Compounds capable of generating initiating free radicals, including infrared absorbers, trichloromethyltriazine and azinium compounds, directly attached to the aromatic ring N, O, include polycarboxylic acid co-initiator having a bound carboxylic acid groups via a methylene group to the S group.

In the present invention, as the photopolymerization initiator, the following formula (III):

(Wherein R ₁ , R ₂ , R ₃ , R ₄ are each independently an alkyl, aryl, alkenyl, alkynyl, cycloalkyl, or heterocyclic group, or R ₁ , R ₂ , R 4) ₃ , 2 or more of R ₄ are bonded together to form a heterocyclic ring having the boron atom)
The boron salt compound containing the boron anion represented by these is used.

Boron salt compounds or onium salt compounds can be suitably used in combination with neutralized phosphoric acid (meth) acrylate monomers. When these ionic initiators are used together with conventional phosphoric acid (meth) acrylate, the ionic form is destroyed by phosphoric acid over time, and the lithographic printing plate precursor becomes unstable and the shelf life is shortened. There was a problem. Such a problem is solved by using the neutralized phosphoric acid (meth) acrylate monomer of the present invention. These photopolymerization initiators may be used alone or in combination of two or more.

Boron salt compounds exhibit a function as a polymerization initiator when used in combination with an infrared absorber. As the boron salt compound, an ammonium salt of a quaternary boron anion represented by the following formula is preferable.

Wherein R ⁴ , R ⁵ , R ⁶ and R ⁷ are each independently an alkyl group, aryl group, alkaryl group, allyl group, aralkyl group, alkenyl group, alkynyl group, alicyclic group, or saturated Or an unsaturated heterocyclic group, wherein at least one of R ¹ , R ² , R ³ and R ⁴ is an alkyl group having 1 to 8 carbon atoms, and R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ independently represents a hydrogen atom, an alkyl group, an aryl group, an allyl group, an alkaryl group, an aralkyl group, an alkenyl group, an alkynyl group, an alicyclic group, or a saturated or unsaturated heterocyclic group. )

Among these, tetra n-butylammonium triphenyl boron, tetra n-butylammonium trinaphthyl boron, tetra n-butylammonium tri (pt-butylphenyl) boron, and tetramethylammonium can be efficiently exhibited. n-butyltriphenylboron, tetramethylammonium n-butyltrinaphthylboron, tetramethylammonium n-octyltriphenylboron, tetramethylammonium n-octyltrinaphthylboron, tetraethylammonium n-butyltriphenylboron, tetraethylammonium n- Butyl trinaphthyl boron, trimethyl hydrogen ammonium n-butyl triphenyl boron, triethyl hydrogen ammonium n-butyl triphenyl C arsenide, tetra hydrogensulfate ammonium n- butyl triphenyl borate, tetramethylammonium n- butylboron, etc. tetraethylammonium n- butylboron can be preferably used.

When the boron salt compound is used in combination with an infrared absorber, radicals are generated by irradiation with infrared rays, and a function as a polymerization initiator can be exhibited.

The content of the boron salt compound is preferably in the range of 0.1 to 15% by mass, particularly preferably in the range of 0.5 to 7% by mass, based on the solid content of the image forming layer. When the content of the boron salt compound is less than 0.1% by mass, the polymerization reaction becomes insufficient, the curing becomes insufficient, the image portion of the obtained negative planographic printing plate becomes weak, and the content of the boron salt compound is 15 When it exceeds mass%, the polymerization reaction does not occur efficiently. Moreover, you may use together 2 or more types of (B) boron salt compounds as needed.

An onium salt compound is a salt composed of a cation having one or more onium ion atoms in the molecule and an anion. The onium ion atom in the onium salt, ^{S +} in sulfonium, iodonium of ^{I +, N +} in ammonium, ^{P +} atom in phosphonium, may be mentioned _N ^{2 +} and diazonium. Among these, as preferable onium ion atoms, S ⁺ , I ⁺ , and N ₂ ⁺ can be fisted. The structure of the onium salt compound includes triphenylsulfonium, diphenyliodonium, diphenyldiazonium, derivatives in which alkyl groups and aryl groups are introduced into the benzene ring of these compounds, and alkyl groups and aryl groups in the benzene ring of the compound. The introduced derivative can be fisted.

Examples of the anion of the onium salt compound include a halogen anion, ClO ₄ ⁻ , PF ₆ ⁻ , BF ₄ ⁻ , SbF ₆ ⁻ , CH ₃ SO ₃ ⁻ , CF ₃ SO ₃ ⁻ , C ₆ H ₅ SO ₃ ⁻ , and CH _3. C ₆ H ₄ SO ₃ ⁻ , HOC ₆ H ₄ SO ₃ ⁻ , ClC ₆ H ₄ SO ₃ ⁻ , boron anion and the like can be mentioned.

As the onium salt compound, a combination of an onium salt having S ⁺ in the molecule and an onium salt having I ⁺ in the molecule is preferable from the viewpoint of sensitivity and storage stability. Moreover, as an onium salt, the polyvalent onium salt which has a 2 or more onium ion atom in 1 molecule from the point of a sensitivity and storage stability is also preferable. Here, two or more onium ion atoms in the cation are linked by a covalent bond. Among the polyvalent onium salts, those having two or more onium ion atoms in one molecule are preferable, and those having S ⁺ and I ⁺ in one molecule are more preferable.

The content of the onium salt compound is preferably in the range of 0.1 to 15% by mass, particularly preferably in the range of 0.5 to 7% by mass, based on the solid content of the image forming layer. If the content of the onium salt compound is less than 0.1% by mass, the polymerization reaction may be insufficient, and the sensitivity and printing durability of the resulting negative planographic printing plate precursor may be insufficient. When the amount exceeds 15% by mass, the developability of the obtained negative type lithographic printing original plate deteriorates. Moreover, you may use together 2 or more types of onium salt compounds as needed. Moreover, you may use together a polyvalent onium salt compound and a monovalent onium salt compound.

In addition, an arbitrary accelerator such as a mercapto compound such as mercapto-3-triazole or an amine compound may be added to the photopolymerization initiator.

Preferred photoinitiator systems include ultraviolet, visible, or infrared absorbers, electron acceptors capable of generating initiating free radicals, and can donate electrons and / or hydrogen atoms and / or initiation free. Co-initiators that can form radicals are included. The amount of the radiation absorber is an amount required for the photosensitive composition to become insoluble in a wet developer or dampening water / printing ink after exposure to radiation. The concentration of the radiation absorber is about 0.05 to 3 mol l ⁻¹ cm ⁻¹ , preferably about 0.1 to 1.5 mol l ⁻¹ cm ⁻¹ , more preferably 0.3 to 1.0 mol. It is preferable that the molar absorptance within the range of l ⁻¹ cm ⁻¹ is obtained.

<Support>
As the support for the lithographic printing plate precursor according to the invention, any material can be used as long as the surface is hydrophilic. However, a dimensionally stable plate-like material is preferable, for example, paper, plastic (for example, polyethylene, Paper laminated with polypropylene, polystyrene, etc., and metals such as aluminum (including aluminum alloys), zinc, copper, etc. or alloys thereof (eg silicon, copper, manganese, magnesium, chromium, zinc, lead, Bismuth, nickel alloy), and further, for example, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose butyrate acetate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc. Like plastic Film, the above described metal or alloy can be cited laminated or vapor-deposited paper or plastic films. Of these supports, the aluminum plate is particularly preferred because it is dimensionally remarkably stable and inexpensive. Further, a composite sheet in which an aluminum sheet is bonded on a polyethylene terephthalate film as described in Japanese Patent Publication No. 48-18327 is also preferable. Usually, the thickness is about 0.05 mm to 1 mm.

In the case of a support having a surface of metal, particularly aluminum, graining treatment, anodizing treatment described later, or immersion in an aqueous solution of sodium silicate, potassium fluoride zirconate, polyvinylphosphonic acid, phosphate, etc. It is preferable that surface treatment such as treatment is performed.

Examples of the graining method include mechanical graining, chemical etching, and electrolytic grain as disclosed in JP-A-56-28893. Furthermore, electrochemical graining method that electrochemically grains in hydrochloric acid or nitric acid electrolyte solution, and wire brush grain method that scratches aluminum surface with metal wire, and ball grain method that graines aluminum surface with polishing ball and abrasive. Further, a mechanical graining method such as a brush grain method in which the surface is grained with a nylon brush and an abrasive can be used, and the above graining methods can be used alone or in combination. Among them, the method of making the surface roughness usefully used in the present invention is an electrochemical method of graining chemically in hydrochloric acid or nitric acid electrolyte, and a suitable current density is in the range of 100 to 400 C / dm ² . It is. More specifically, electrolysis is performed in an electrolytic solution containing 0.1 to 50% hydrochloric acid or nitric acid at a temperature of 20 to 100 ° C., a time of 1 second to 30 minutes, and a current density of 100 to 400 C / dm ^2. Is preferred.

The aluminum support thus grained is chemically etched with acid or alkali. When an acid is used as an etching agent, it takes time to destroy the fine structure, which is disadvantageous when the present invention is applied industrially, but it can be improved by using an alkali as the etching agent.

Examples of the alkali agent suitably used include caustic soda, sodium carbonate, sodium aluminate, sodium metasilicate, sodium phosphate, potassium hydroxide, lithium hydroxide and the like. The conditions are 50% and 20 to 100 ° C., and the amount of aluminum dissolved is preferably 5 to 20 g / m ³ .

After the etching, pickling is performed to remove dirt (smut) remaining on the surface. Examples of the acid that can be used include nitric acid, sulfuric acid, phosphoric acid, chromic acid, hydrofluoric acid, and borohydrofluoric acid. In particular, as a method for removing smut after the electrochemical surface roughening treatment, contact with 15 to 65 mass% sulfuric acid at a temperature of 50 to 90 ° C. as described in JP-A-53-12739 is preferable. And the alkali etching method described in Japanese Patent Publication No. 48-28123. In the present invention, the aluminum support preferably has a surface roughness (Ra) of 0.3 to 0.7 μm.

The aluminum support treated as described above is further anodized. The anodizing treatment can be performed by a method conventionally performed in the technical field. Specifically, sulfuric acid, phosphoric acid, chromic acid, oxalic acid, sulfamic acid, benzene sulfonic acid, etc., or a combination of two or more thereof, and when direct current or alternating current is applied to aluminum in aqueous solution or non-aqueous solution, aluminum support An anodized film can be formed on the body surface. The conditions of the anodizing treatment vary depending on the electrolyte used, and cannot be determined unconditionally. In general, however, the concentration of the electrolyte is 1 to 80%, the solution temperature is 5 to 70 ° C., the current density is 0. A range of 5 to 60 amperes / dm ² , a voltage of 1 to 100 V, and an electrolysis time of 10 to 100 seconds is appropriate.

Among these anodizing treatments, in particular, the method of anodizing at high current density in sulfuric acid described in British Patent 1,412,768, and US Pat. No. 3,511,661. The method of anodizing phosphoric acid described in the above as an electrolytic bath is preferable.

In the present invention, the anodic oxide film is preferably 1 to 10 g / m ² , and if it is less than 1 g / m ² , the plate tends to be damaged, and if it exceeds 10 g / m ² , a large amount of power is required for production. It is economically disadvantageous. Preferably, it is 1.5-7 g / m ² , more preferably 2-5 g / m ² .

In the present invention, the support may be subjected to sealing treatment after graining treatment and anodizing. Such sealing treatment is performed by immersing the support in a hot aqueous solution containing hot water and an inorganic salt or an organic salt, a steam bath, or the like. Further, the support used in the present invention is treated with silicate treatment with alkali metal silicate, treatment with potassium fluoride zirconate, treatment with aqueous solution of polyamine sulfonic acid, polyvinyl phosphonic acid, polyacrylic acid or polymethacrylic acid. Surface treatment such as may be performed.

In the present invention, an image forming layer made of the above-described photosensitive composition is applied onto a support (in the case of an aluminum plate, an aluminum plate that has been appropriately surface-treated as described above) is preferably used. Accordingly, a lithographic printing plate precursor is formed by further applying a protective layer. Since the photosensitive composition of the present invention has very good adhesion to the support, it is not necessary to provide an organic or inorganic undercoat layer between the image forming layer and the support, but it is provided if necessary. Also good. Although not necessary, a sol-gel treatment in which a functional group capable of causing an addition reaction by a radical is disclosed as disclosed in JP-A-7-159983 may be applied.

The lithographic printing plate precursor can be developed after being directly exposed to a second harmonic of a semiconductor laser (SHG-LD, 350 to 600 nm), a YAG-SHG laser, an lnGa N-based short-wave semiconductor laser, etc. In order to be able to handle in a room, it is preferable to use a high-power laser having the maximum intensity from the near infrared to the infrared region. As such a laser having the maximum intensity from the near infrared to the infrared region, various lasers having the maximum intensity in the wavelength region of 760 to 1200 nm are used. In addition, a heating process for 1 second to 5 minutes at a temperature of 50 ° C. to 150 ° C. may be provided for the purpose of increasing the curing rate of the photopolymerizable image forming layer after image exposure and before development.

A conventionally known alkaline aqueous solution can be used as the developer used in the development process. For example, sodium silicate, potassium, tribasic sodium phosphate, potassium, ammonium, dibasic sodium phosphate, potassium, ammonium, sodium carbonate, potassium, ammonium, sodium bicarbonate, potassium Inorganic alkaline agents such as ammonium, sodium borate, potassium, ammonium, sodium hydroxide, ammonium, potassium and lithium can be mentioned. Moreover, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, An organic alkali agent such as ethyleneimine, ethylenediamine, or pyridine may be used in combination. These alkali agents may be used alone or in combination of two or more.

Further, the surfactants described below may be added to the developer. Examples of the developer surfactant include polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene alkyl ethers such as polyoxyethylene stearyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene nonyl phenyl ether, and the like. Polyoxyethylene alkyl allyl ethers, polyoxyethylene alkyl esters such as polyoxyethylene stearate, sorbitan monolaurate, sorbitan monostearate, sorbitan distearate, sorbitan monooleate, sorbitan sesquioleate, sorbitan Monoglyceride alkyl esters such as sorbitan alkyl esters such as trioleate, glycerol monostearate and glycerol monooleate Nonionic surfactants such as alkylbenzene sulfonates such as sodium dodecylbenzenesulfonate, alkylnaphthalenesulfonates such as sodium butylnaphthalenesulfonate, sodium pentylnaphthalenesulfonate, sodium hexylnaphthalenesulfonate, sodium octylnaphthalenesulfonate Anionic surfactants such as alkyl sulfonates such as sodium lauryl sulfate, alkyl sulfonates such as sodium dodecyl sulfonate, sulfosuccinate ester salts such as sodium dilauryl sulfosuccinate: alkyl betaines such as lauryl betaine and stearyl betaine, Amphoteric surfactants such as amino acids can be used, but anionic surfactants such as alkylnaphthalene sulfonates, alkyls are particularly preferable. Tines such a nonionic surfactant having a polyoxyalkylene ether group represented by the formula (2).

R ¹ —O— (R ² —O) _n H (2)
{In Formula (2), R ¹ is an optionally substituted alkyl group having 3 to 15 carbon atoms, an optionally substituted aromatic hydrocarbon group having 6 to 15 carbon atoms, or a substituent. A heteroaromatic cyclic group having 4 to 15 carbon atoms which may have a substituent (the substituent is an alkyl group having 1 to 20 carbon atoms, a halogen atom such as Br, Cl or I, an aromatic group having 6 to 15 carbon atoms) And hydrocarbon groups, aralkyl groups having 7 to 17 carbon atoms, alkoxy groups having 1 to 20 carbon atoms, alkoxycarbonyl groups having 2 to 20 carbon atoms, and acyl groups having 2 to 15 carbon atoms). R ² represents an optionally substituted alkylene group having 1 to 10 carbon atoms (the substituent includes an alkyl group having 1 to 20 carbon atoms and an aromatic hydrocarbon group having 6 to 15 carbon atoms). N represents an integer of 1 to 100}. In addition, the part of (R ² —O) _{n in} the formula (2) may be two or three groups within the above range. Specific examples include a combination of random or flocked combinations of ethyleneoxy and propyleneoxy, ethyleneoxy and isopropyloxy, ethyleneoxy and butyleneoxy, ethyleneoxy and isobutylene, etc. it can.

These surfactants can be used alone or in combination. The content of these surfactants in the developer is preferably 0.1 to 20% by mass in terms of active ingredients.

In the present invention, in addition to the above components, the following components can be used in combination with the developer as necessary. For example, benzoic acid, phthalic acid, p-ethylbenzoic acid, pn-propylbenzoic acid, p-isopropylbenzoic acid, pn-butylbenzoic acid, pt-butylbenzoic acid, p-2-hydroxyethylbenzoic acid Organic carboxylic acids such as acid, decanoic acid, salicylic acid, 3-hydroxy-2-naphthoic acid; organic solvents such as isopropyl alcohol, benzyl alcohol, ethyl cellosolve, butyl cellosolve, phenyl cellosolve, propylene glycol, diacetone alcohol; Agents, reducing agents, dyes, pigments, water softeners, preservatives, antifoaming agents and the like.

The development of the lithographic printing plate precursor according to the present invention with the developer is performed according to a conventional method, for example, by immersing the exposed lithographic printing plate precursor in a developer at a temperature of about 0 to 60 ° C., preferably about 15 to 40 ° C. For example, rubbing with a brush. Furthermore, development processing may be performed using an automatic developing machine, in which case the developer will be fatigued depending on the amount of processing, so that replenisher or fresh developer may be used to restore processing capacity. May be. When a protective layer is provided on the image forming layer, the above-described developer may be used to remove the protective layer and the unexposed portion of the image forming layer at the same time, or The protective layer may be removed first with warm water, and then the unexposed image forming layer may be removed with a developer. These water or warm water can contain, for example, a preservative described in JP-A-10-10754, an organic solvent described in JP-A-8-278636, and the like.

The lithographic printing plate precursor thus developed is preferably washed with water as described in JP-A Nos. 54-8002, 55-11545, and 59-58431. And post-treatment with a desensitizing solution containing a rinsing solution containing a surfactant and the like, gum arabic, starch derivatives and the like. These treatments can be used in various combinations for the post-treatment of the lithographic printing plate precursor according to the invention.

In consideration of environmental problems, development can also be performed using so-called water having a neutral pH range. In this case as well, for the purpose of improving the developability, the surfactant described in the description of the developer and the above-described desensitizing solution for the purpose of desensitizing the plate surface after development can be added to water as a developing solution.

The lithographic printing plate precursor obtained by the above treatment can be improved in printing durability by a known heat treatment such as post-exposure treatment or burning. Next, the lithographic printing plate obtained by the above processing is loaded on an offset printing machine and used for printing a large number of sheets.

The obtained lithographic printing plate precursor can also be used for on-machine development type. The obtained lithographic printing plate precursor can be used for a plate that can be attached to a printing press plate cylinder as it is after imagewise exposure and printing can be started.

The invention is explained in more detail in the following examples, which are not intended to limit the invention.
The compounds represented using abbreviations in the following examples are as follows.
PGME: Propylene glycol monomethyl ether MEK: Methyl ethyl ketone Polymer A: Copolymer of methacrylic acid, allyl methacrylate, methyl methacrylate

IR dye A: cyanine infrared absorbing dye shown below

DPHA: Dipentaerythritol hexaacrylate, available from Nippon Kayaku Co., Ltd.

Dye B: Triphenylmethane dye shown below

MDP: Hindered phenol type polymerization inhibitor shown below, available from Sumitomo Chemical Co., Ltd.

TAZ-104: Trihalomethyltriazine compounds shown below, available from Midori Chemical Co., Ltd.

P3B: Boron compounds shown below, available at Showa Denko KK

N3B: Boron compounds shown below, available from Showa Denko KK

CGI-909: Boron compounds shown below, available from Ciba Specialty Chemicals Co., Ltd.

Na / TPB: Boron compound having the structure shown below

Zonyl FSO: Nonionic fluorosurfactant Zonyl FSA: Anionic fluorosurfactant, supplied as a 25% aqueous solution.

Initiator A: Boron compound with the structure shown below

ACA230AA: an acrylic resin containing an alkali-soluble side chain ethylenically unsaturated double bond group, available from Daicel Chemical Industries, Ltd. Supplied as a 53% solution.

Irgacure 250 is an iodonium salt available from Ciba specialty Chemicals, Tarrytown, NY as a 75% propylene carbonate solution and has the formula iodonium, (4-methylphenyl) [4- (2-methylpropyl) phenyl], -With hexafluorophosphate.

IR absorbing dye 1 is represented by the following formula:

Fluorinated polymer solutions P-1 to P-9 used in the examples are shown below. The ratio in a formula represents mol%.

P-1: 25% methyl isobutyl ketone solution of the following polymer

P-2: 25% methyl isobutyl ketone solution of the following polymer

P-3: 25% methyl isobutyl ketone solution of the following polymer

P-4: 25% methyl isobutyl ketone solution of the following polymer

P-5: 25% methyl isobutyl ketone solution of the following polymer

P-6: 25% methyl isobutyl ketone solution of the following polymer

P-7: 25% methyl isobutyl ketone solution of the following polymer

P-8: 25% methyl isobutyl ketone solution of the following polymer

P-9: 25% methyl isobutyl ketone solution of the following polymer

In the examples, the contents of the compositions A, B and C serving as the base of the radiation-sensitive composition used are as follows.

Urethane acrylate was prepared by reacting Desmodur N100 (aliphatic polyisocyanate resin based on hexamethylene diisocyanate, available from Bayer Corp., Milford, CT) with hydroxyethyl acrylate and pentaerythritol triacrylate. Used as a 40% methyl ethyl ketone solution.

Graft copolymer 1 is a polymer grafted with poly (oxy-1,2-ethanediyl), α- (2-methyl-1-oxo-2-propenyl) -ω-methoxy-, ethenylbenzene. Combined with the ingredients in Table 1 as a 25% dispersion in a solvent of 80% n-propanol / 20% water. Graft copolymer 2 is a methoxy polyethylene glycol methacrylate-allyl methacrylate graft copolymer, which is added to the ingredients in Table 1 as a 10% dispersion in methyl ethyl ketone.

Examples 1 to 4, Comparative Examples 1 and 2
A radical initiator, a boron salt compound, and a fluorinated polymer P-1 were added to the base composition A to obtain Examples (inventions) 1 to 4, and a fluorinated surfactant was used instead of the fluorinated polymer. As Comparative Examples 1 and 2, final lithographic printing plate precursors were evaluated. Fluorosurfactants Zonyl FSO and Zonyl FSA are surfactants having a hydrophilic group.

(1) Production of support body An aluminum plate having a thickness of 0.30 mm was degreased with an aqueous sodium hydroxide solution, and this was electropolished in a 2% hydrochloric acid bath to obtain a center line average roughness (Ra) of 0.6 μm. I got a grained plate. Then, this grained plate was anodized at a current density of 2 A / dm ² in a 20% sulfuric acid bath to form an oxide film of 2.7 g / m ² to obtain an aluminum support.

(2) Application of photosensitive solution A coating solution for each example and each comparative example was prepared, and this coating solution was coated on the aluminum support with a bar coater and dried at 115 ° C. for 1 minute to produce a lithographic printing plate. I got the original version. At this time, the amount of the dried coating film was 1.2 g / m ² .

Evaluation Test The prepared lithographic printing plate precursor was tested for developability, sensitivity, printing durability, and blooming. The test method is as follows.

<Developability>
9.3 L of Kodak Co., Ltd. concentrated type developer and 32.7 L of tap water were charged into an automatic processor PK1310news manufactured by Kodak Co., Ltd., and the developing temperature was set to 30 ° C. The washing tank was charged with water and the gum tank was charged with 1 + 1 dilution of NF-3 gum solution. Using the prepared lithographic printing plate precursor, the development time (residence time of the lithographic printing plate precursor in the developer) was changed in various ways, and the minimum time for completion of development was expressed in seconds as developability.

<Sensitivity>
The prepared lithographic printing plate precursor was exposed using various exposure energy amounts using an exposure machine Magnus 800 plate setter manufactured by Kodak. A Kodak automatic developing machine PK1310news was charged with 9.3 L of Kodak concentrated developer and 32.7 L of tap water, the development temperature was set to 30 ° C., and the development time was set to 12 seconds. The washing tank was charged with water and the gum tank was charged with 1 + 1 dilution of NF-3 gum solution. The exposed lithographic printing plate precursor was developed with an automatic processor, and mJ / cm ^{2 was} displayed with the minimum exposure amount at which an image could be obtained as sensitivity.

<Print durability>
The prepared lithographic printing plate precursor was exposed with an exposure energy of 120 mJ / cm ² using an exposure machine Magnus 800 plate setter manufactured by Kodak. A Kodak automatic developing machine PK1310news was charged with 9.3 L of Kodak concentrated developer and 32.7 L of tap water, the development temperature was set to 30 ° C., and the development time was set to 12 seconds. Further, tap water was charged into the water washing tank, and NF-3 gum solution was charged into the gum tank at a 1 + 1 dilution. The exposed lithographic printing plate precursor was developed with an automatic developing machine and printed with an S-26 lithographic printing machine manufactured by Comorie. The maximum number of prints that gives a clear image was displayed as the printing durability.

<Blooming>
The prepared lithographic printing plate precursor was left for 7 days at 40 ° C. and 80% RH. The neglected lithographic printing plate precursor was observed in detail, and the degree of crystallization was judged on the assumption that blooming had occurred with respect to the crystallization of the photosensitive composition component on the surface of the image forming layer.
A: Crystallization of the photosensitive composition component did not occur on the surface of the image forming layer.
Δ: Crystallization of the photosensitive composition component occurred on the surface of the image forming layer, but the image forming layer did not become white due to poor curing during exposure and development, and was not a problem in practical use.
X: The photosensitive composition component was crystallized on the surface of the image forming layer, and the image forming layer was white due to poor curing during exposure and development.

Examples 5 to 9, Comparative Examples 3 and 4
To the base composition B, a radical initiator, a boron salt compound, and a fluorinated polymer P-1 were added to give Examples (Inventions) 6 to 9, and a fluorinated surfactant was used instead of the fluorinated polymer. As Comparative Examples 3 and 4, final lithographic printing plate precursors were evaluated. The fluorine-based surfactant Zonyl FSO is a surfactant having a hydrophilic group.

Examples 10 to 17 and Comparative Examples 5 to 7
To each of the base compositions A, radical initiators, boron salt compounds, and fluorinated polymers P-1 to 9 were added, and the final lithographic plates were prepared as Examples (Inventions) 10 to 17 and Comparative Examples 5 to 7. The printing plate precursor was evaluated. Comparative Examples 5 and 6 are examples using a fluorinated polymer having a hydrophilic group in the molecule and having a function as a surfactant.

Examples 18 to 23, Comparative Examples 8 to 10
To each of the base compositions B, a radical initiator, a boron salt compound, and a fluorinated polymer P-1 to 9 were added, and examples (inventions) 18 to 23 and comparative examples 8 to 10 were used as final lithographic plates. The printing plate precursor was evaluated. Comparative Example 8 and Comparative Example 9 are examples using P-6 and P-9 having a polyoxyethylene group in the polymer side chain and having surface activity.

<On-press development type lithographic printing plate>
(1) Production of support body An aluminum plate having a thickness of 0.30 mm was degreased with an aqueous sodium hydroxide solution, and this was electropolished in a 2% hydrochloric acid bath to obtain a center line average roughness (Ra) of 0.6 μm. I got a grained plate. Subsequently, this grained plate was anodized in a 20% sulfuric acid bath at a current density of 2 A / dm ² to form an oxide film of 2.7 g / m ² . Thereafter, the aluminum plate was immersed in a 1% polyvinylphosphonic acid aqueous solution kept at 60 ° C. for 20 seconds, washed with water and dried to obtain an aluminum support.

(2) Application of photosensitive solution A coating solution for each example and each comparative example was prepared, and this coating solution was coated on the aluminum support with a bar coater and dried at 115 ° C. for 1 minute to produce a lithographic printing plate. I got the original version. At this time, the amount of the dried coating film was 1.2 g / m ² .

<Sensitivity>
The prepared lithographic printing plate precursor was exposed using various exposure energy amounts using an exposure machine Magnus 800 plate setter manufactured by Kodak. A Kodak automatic developing machine PK1310news was charged with 9.3 L of Kodak concentrated developer and 32.7 L of tap water, the development temperature was set to 30 ° C., and the development time was set to 12 seconds. Further, water was added to the washing tank, and NF-3 gum solution was diluted with 1 + 1 tap water and charged into the gum tank. The exposed lithographic printing plate precursor was developed with an automatic processor, and mJ / cm ^{2 was} displayed with the minimum exposure amount at which an image could be obtained as sensitivity.

Example 24, Comparative Example 11
A radical initiator, a boron salt compound, and a fluorinated polymer P-1 were added to the base composition C to obtain Example (Invention) 24, and a fluorinated surfactant Zonyl FSA was used instead of the fluorinated polymer. As Comparative Example 11, on-press development was performed to evaluate each final lithographic printing plate precursor.

As the on-press development method, the exposed lithographic printing plate precursor is attached to the printing press, the water roller is lowered, the printing press is rotated 10 times, dampening water is supplied to the plate surface, and the ink roller is lowered. The on-press development was completed by rotating the printing machine 10 times to remove the unexposed image forming layer on the plate surface. When the on-press development is completed by the above method and the image forming layer in the unexposed area is removed, the on-press development is good, and the on-press development is not completed by the above method, and the rotation speed of the ink roller is increased from 10 rotations. What was necessary was defined as on-machine development failure.

<Sensitivity>
The prepared lithographic printing plate precursor was exposed using various exposure energy amounts using an exposure machine Magnus 800 plate setter manufactured by Kodak. The plate was attached to a Roland 200 printer manufactured by Man Roland, and the on-press development processing was performed. After on-press development, printing was started by passing printing paper, and mJ / cm ² display was performed with the minimum exposure amount at which an image can be obtained as sensitivity.

<Blooming>
The prepared lithographic printing plate precursor was left for 7 days at 40 ° C. and 80% RH. The neglected lithographic printing plate precursor was observed in detail, and the degree of crystallization was judged on the assumption that blooming occurred with respect to the crystallization of the photosensitive composition on the surface of the image forming layer.
A: Crystallization of the photosensitive composition did not occur on the surface of the image forming layer.
Δ: Crystallization of the photosensitive composition occurred on the surface of the image forming layer, but the image forming layer did not become white due to poor curing at the time of exposure and development, and was not a practical problem.
X: Crystallization of the photosensitive composition occurred on the surface of the image forming layer, and it was a practically problematic level such as whiteout of the image forming layer due to poor curing during exposure and development.

Example 25, Comparative Example 12
A radical initiator, a boron salt compound, and a fluorinated polymer P-1 were added to the base composition C to obtain Example 25 (invention), and a fluorinated surfactant Zonyl FSO was used instead of the fluorinated polymer. As Comparative Example 12, on-press development was performed, and each final lithographic printing plate precursor was evaluated.

The lithographic printing plate precursor prepared by the time-dependent acceleration test was allowed to stand for 7 days under heating at 50 ° C., and the decrease in sensitivity from the exposure sensitivity of the lithographic printing plate precursor not left under heating was evaluated. Using a Kodak exposure machine Magnus 800 plate setter, exposure was performed with various amounts of exposure energy. A Kodak automatic developing machine PK1310news was charged with 9.3 L of Kodak concentrated developer and 32.7 L of tap water, the developing temperature was set to 30 ° C., and the developing time was set to 12 seconds. The washing tank was charged with water and the gum tank was charged with 1 + 1 dilution of NF-3 gum solution. The exposed lithographic printing plate precursor was developed with an automatic processor, and mJ / cm ^{2 was} displayed with the minimum exposure amount at which an image could be obtained as sensitivity.

Claims (11)

1. A lithographic printing plate precursor comprising a support and an image forming layer containing a radiation-sensitive composition containing a radical polymerizable component, an infrared absorber and a radical polymerization initiator,
   A lithographic printing plate precursor, wherein the radiation-sensitive composition comprises a fluorinated copolymer having substantially no hydrophilic portion.
2. The lithographic printing plate precursor as claimed in claim 1, wherein the fluorinated copolymer (A) having substantially no hydrophilic portion comprises at least two monomer units represented by the following formulas (I) and (II).
   Formula (A):
   

   

   (In the above formula,
   R ₁ and R ₂ are hydrogen or a methyl group,
   Rf represents an aliphatic group substituted with a fluorine atom;
   Z represents a divalent organic group, and X represents any organic group substantially free of a cationic group, an anionic group, an acidic group, or a polyoxyethylene group)
3. The lithographic printing plate precursor as claimed in claim 2, wherein the fluorinated copolymer comprises 10 to 97 mol% of the monomer unit of the formula (I) and 3 to 90 mol% of the monomer unit of the formula (II).
4. The lithographic printing plate precursor as claimed in claim 2 or 3, wherein Rf in the formula (A) is an aliphatic group having 1 to 20 carbon atoms in which at least two of the hydrogen atoms of the terminal carbon are substituted with fluorine atoms.
5. X in the formula (A) represents a —CO—A—Y group, A represents an oxygen atom or NR ⁴ —, wherein R ⁴ represents a hydrogen atom or a monovalent hydrocarbon having 1 to 10 carbon atoms. 3 represents a group, and Y is selected from the group consisting of an optionally substituted alkyl group, an optionally substituted aryl group, and a monovalent organic group having an unsaturated group. The lithographic printing plate precursor as described in any one of ~ 4.
6. The fluorinated copolymer having no hydrophilic portion is represented by the following formula (1):
   

   

   (In the formula, R represents a hydrogen atom or a hydrocarbon group such as an alkyl group, an alkenyl group, and an aryl group.)
   The lithographic printing plate precursor according to any one of claims 1 to 5, further comprising a monomer unit having a maleimide skeleton represented by the formula:
7. The lithographic printing plate precursor as claimed in any one of claims 1 to 6, wherein the radical polymerization initiator is selected from a sulfonium salt, an iodonium salt, a diazonium salt, and a triazine compound containing a halomethyl moiety.
8. The lithographic printing plate precursor according to any one of claims 1 to 7, wherein the radiation-sensitive composition contains at least one boron salt compound containing a boron anion represented by the formula (III).
   

   

   (Wherein R ₁ , R ₂ , R ₃ , R ₄ are each independently an alkyl, aryl, alkenyl, alkynyl, cycloalkyl, or heterocyclic group, or R ₁ , R ₂ , R 4) ₃ , 2 or more of R ₄ are bonded together to form a heterocyclic ring having the boron atom)
9. The lithographic printing plate precursor as claimed in any one of claims 1 to 8, wherein the radiation-sensitive composition further comprises a binder resin.
10. The lithographic printing plate precursor as claimed in any one of claims 1 to 9, wherein the image forming layer is developable with an alkaline aqueous solution.
11. 10. The lithographic printing plate precursor as claimed in claim 1, wherein the image forming layer is developable with a fountain solution and / or printing ink.